Recording device for concrete mixing drums



R. OSBORNE ET AL RECORDING DEVICE FOR CONCRETE MIXING DRUMS Nov. 10, 1953 w 4 Sheets-Sheet 1 Filed Feb. 5, 1952 .E: S 2 VOW. no Z 00 M WT M 3 we mgfi a g ATrOQA/EY.

1953 R. G. OSBORNE ET AL 2,658,731

RECORDING DEVICE FOR CONCRETE MIXING DRUMS Filed Feb. 5, 1952 4 Sheets-Sheet 2 "In," I

liiannmlammg B05527 0 Bar/aw, I

NO 1953 R. G. OSBORNE ET AL 3 RECORDING DEVICE FOR CONCRETE MIXING DRUMS Filed Feb. 5, 1952 4 Sheets-Sheet 3 and DESIGN and MIXING 17MB CERTIFICATE TIME or PouQme THE CONCRETE ME OF LOADING and Aooms WQTER INVENTORS. RAYMOND 6. 0550mm,

1. 06527 0 Bork/M 1953 R. G. OSBORNE ETAL 2,658,731

RECORDING nsvzcs FOR CONCRETE MIXING DRUMS Filed Feb. 5, 1952 4 Sheets-Sheet 4 E90 0& 04 5%- lllf firm/mes. .140 RAYMOND 6. 0350mm,

Raeer 0 Bane/A4 ATTOENEY- Patented Nov. 10, 1 953 UNITED STATES PATENT OFFICE RECORDING DEVICE FOR CONCRETE MIXING DRUMS Application February 5, 1952, Serial No. 269,938

14 Claims.

This invention pertains to means and methods of accurately controlling and recording mixing conditions of concrete so as to insure the delivery of concrete in proper condition to a job.

In recent years large quantities of concrete have been delivered to job sites from central proportioning plants by means of vehicle provided with mixing devices, the sand, gravel, cement and water being usually mixed in such a device during transit from the central plant to the job site where the concrete is to be poured. Although the proportions of sand, gravel, cement and water are carefully measured by Weight into the mixer carried by the vehicle, the rate of rotation of the mixer during transit, as well as the total time consumed during transportation from the central plant to the job, can vary appreciably. It is well known that rotation of a mixing drum at a low rate of speed results in poor mixing of concrete with consequent low concrete strength, while rotation at too fast a rate of speed creates a centrifugal force which prevents proper cascading and uniform mixing of the concrete which again reduces the structural strength of the resulting concrete. It is well understood that the rate of rotation of the mixer is an important factor; every mixing device has an optimum rotation speed at which the contents are more thoroughly agitated and more homogeneously mixed than at other speeds.

Heretofore, no means were provided to positively factually establish firm data pertaining to the actual number of minutes of mixing of each batch of concrete as well as the rate of mixing speed of the mixer drum minute by minute. The operator of the vehicle may have consumed a long period of time in moving the batch to the job or a short period of time; he may have run the mixer at one speed or another; the mixer may have run at an excessive speed for a certain time interval and was stationary during another period of time. As a result, one batch of concrete may have been properly mixed and may show the desired slump consistency whereas another batch may have been improperly mixed and have failed to develop desired workability and plasticity.

The present invention is directed toward means and methods whereby the inspector on the job is supplied with a positive record of the precise conditions of time and rate of rotation of the mixer, so that the characteristics of the concrete being delivered to the job are known. Moreover, the present invention provides a complete record upon which all essential data regarding the concrete, the mix used, the manner and time of mixing and other details are presented, thereby eliminating arguments and insuring the utilization of only acceptable concrete of a uniform character.

An object of the present invention, therefore, is to disclose and provide a simple and efficient means whereby an accurate record of mixing times and conditions are attained.

Another object of the present invention is to design a device for providing such a record of mixing times and conditions which may be readily associated with rotatable mixing drums of various shapes and sizes.

A further object of this invention is to design and provide a device as above described which may be driven by a rotatable mixing drum and which is provided with means for making a foolproof record or the time periods during which the mixing drum is rotated at a preselected desired speed.

Still another object of this invention is to design and provide a device as above described which includes intermittently actuatable switch means which are cooperable with other switch means actuated only when the mixing drum is rotated at a preselected speed for recording time periods during which said mixing drum was so rotated.

Generally speaking, this invention contemplates a device for measuring and recording the time periods during which a mixing drum rotates at a preselected desired speed, said device being adjustably mounted adjacent to the mixing drum. The device may comprise a hollow rotatable housing enclosing a speed responsive means which is axially movable and driven by contact of the device with the surface of the mixing drum. An intermittently actuatable switch means is also carried within the housing and operable by rotation of the housing. The speed responsive means may carry a switch actuator means which is cooperable with a selectively positionable switch means for completing, together with the intermittently actuatable switch means, a circuit when the mixing drum is rotating at a preselected speed. This circuit, when complete, causes actuation of a marking means for indicating on a time driven chart, the time periods at which the mixing drum was rotating at a selected speed, speeds which were too slow or too fast, and a stop condition. The time driven chart may be suitably located in the cab of the truck carrying the mixing drum. In one embodiment of this invention a foolproof record of the time periods during which the drum was rotating at a desired selected speed is made by burning such a record on the chart by means of suitably arranged spark coils.

Other objects and advantages of this invention will be readily apparent from the following description of the drawings.

In the drawings:

Fig. 1 is a side elevational view of a well-known type of mixing truck capable of mixing a batch of concrete while in transit.

Fig. 2 is a fragmentary end view of a device embodying this invention showing a mounting of the device to the frame of the truck and the'device in rolling contact with the mixing drum.

Fig. 3 is a fragmentary side view of the device shown in Fig. 2.

Fig. 4 is an enlarged sectional view of the device shown in Fig. 3, the section being taken in a vertical plane passing through the axis of said device.

Fig. 5 is a fragmentary view taken from a transverse plane indicated by line V-V of Fig. 4.

Fig. 6' is a fragmentary view partiallytaken in the plane indicated at line VI-VI of Fig. 4.

Fig. 7 is an enlarged fragmentary view in'section showing the means for axially adjusting'one of the switch means.

Fig. 8 is a fragmentary view illustrating the speed responsive device in the preselected speed position wherein the adjustable means is closed.

Fig. 9 is a fragmentary view of the speed responsive device illustrating its position at a speed lower than a desired selected speed of rotation of the mixing drum.

Fig. 10 is a diagrammatic view illustrating a circuit means for actuating the recording means.

Fig. 11 is a view of one side of a recording chart used with this device for recording pertinent data relating to the batch of concrete being moved in transit.

Fig. 12. is a diagrammatic view of a circuit means for actuating a modification of the recording. means wherein spark coils are used to burn the record on a recording chart.

Fig. 13 is a fragmentary view of a chart illustrating the pattern in which the burned record is made.

Fig. 14 is a diagrammatic view of a different modification of the circuit means for producing a record of the operation of a concrete mixer.

Fig. 15 is a diagrammatic view of a circuit means and recording means so that operational data concerning the job site concrete mixer may be recorded.

It has been found that to properly mix the sand; aggregate; cement and water so that acceptable concrete will be delivered to the job, an exemplary mixing drum of 4 to 5 yards capacity has an optimum peripheral speed of about 200 feet per minute. This speed should be achieved for an aggregate time period of from 12 to 16 minutes, the total time period being made either by one continuous time period or by a plurality of shorter time periods which aggregate 16 minutes. To deliver properly mixed acceptable concrete to a job, it is important that the driver be provided with information as to the time periods when the mixing drum is rotated at selected optimum speed so that the mixing may be completed when he arrives at the job. Also a permanent foolproof record of the mixing times and condition is of importance to insure that nonacceptable concrete is not used and to prevent and resolve any arguments as to mixing conditions.

Generally speaking, the device IQ of the present invention includes a rotatable hollow housing 2!] supported for rolling contact with a peripheral surface of a mixing drum 2|. Speed responsive means generally indicated at 22 are driven within housing 20 and carry a switch actuator means 23 for cooperable contact with a selectively adjustable switch means 24. Also within the housing isan intermittently actuated switch means 25 which is cooperable with the switch means 24 for closing and completing a circuit for causing actuation of a marking mean generally indicated at 26. The marking means 26 records on a removable chart 25 which is rotatably driven by a suitable spring-actuated time clock 28 (Fig. 12), the chart, marking means. and time clock being carried within the cab of the truck.

In Fig. 1 is illustrated a truck carrying a concrete mixing drum 2| of well known construction and operation. The drum 2| is rotatable about an inclined axis and may be supported from a suitable frame 29 carried by the bed of the truck. An engine 3| drives said mixing drum 2| through a gear arrangement generally indicated at 32. The rate of rotation of the drum may be controlled by suitable means by the driver from within the cab of the truck.

The device |9 embodying this invention may be carried by the frame 29 by a bracket 33'seoured to an adjacent frame member by a suitable nut and bolt assembly 34. The bracket 33 includes an out wardly projecting portion 35 having. a'circular bearing face 35a for engagement with a bearing face 35 provided on a corresponding offset portion 31a'on a coupling member 31. The off-set portions 35 and 37a may be, pivotallyconnected by a suitable center pin and key assembly 38. The coupling member 3lincludes'an end ele'-. ment 39 lying in a plane at right angles to said faces 35a and 35 for connection to a hollow boxlike member 48. The member 40 pivotallycarries a U-shaped yoke 4| by means of a pivot rod42 extending through a pair of upstanding spaced lugs'43 on said yoke 4| and suitably. aligned openings: M provided in said member 49.

The yoke is adjustably spring-biased against mixing drum 2| by means ofa spring 45 connected at one end as at 4'6 to a bracket 41 carried. by yoke 4|. At its other end, spring 45 may be connected to a threaded adjusting rod 48 which is carried by a lug 49 connected to the member 40.

The generally cylindrical housing 20 may be supported between a pair of spaced opposed leg members 50 forming the yoke 4|. The housing 20 (Fig. 4) may be formed of two housing portions 5| and 52 adapted to be joined adjacent the mid-section of the housing. Each housing portion 5| and 52 includes a radially outwardly extending annular flange 53 and 54 respectively secured together by any suitable means such as circumferentially spaced bolt and nut assemblies (not shown). Mounted on flanges 53 and 54 may be a rubber tire 55 adapted to contact as at 56 an outer peripheral surface of mixing drum 2|.

The housing portion 5| is provided with an axially extending annulus 51 adapted to be received within a cooperative internal recess 58 on the housing portion 52 for positively positioning said portions in axial alignment.

At one end of housing 20 a stub axle 60 may be fitted in end wall SI of housing portion 52 as at 62. The outer end of axle 60 may be journably supported by the adjacent leg member 50 of the yoke 4|.

At the other end of housing 20, housing portion 5| may be provided with an end wall 63 having an inwardly extending internal annular boss 64 affording a seat as at 65 for a bearing means 56. Spaced from end wall 63 may be an annular partition wall 6! fitted as at 68 to a complementary interior surface on housing portion 5I. The wall 61 is provided with an axial opening 69 within which is received and fitted a suitable bearing means I0.

The bearing means 66 and 10 support a hollow stub axle II, the outer surface of said hollow axle II being formed with an intermediate shoulder 12 for spacing said bearing means 66 and 70. The outer end of the hollow axle II may be received within suitable journal means provided in the adjacent leg 50 of the yoke 4|.

Speed responsive means 22 are axially carried and driven within housing 20 by a governor shaft I4 journably mounted at opposite ends by bearing means I5 carried within a central opening in a partition 16 fitted in housing portion 5| and by a bearing means 11 carried in a central opening of a partition 18 fitted within housing portion 52. The shaft 14 includes an extension 10 upon which may be mounted a gear 80 for rotatably driving shaft I4. The gear 80 may be meshed with a spur gear 8| carried by a stub shaft 82 antifrictionally supported as at 83 and 84 in partitions I6 and 61 respectively. The stub shaft 82 carries at its outboard end a gear 85 meshed with a stationary gear 86 carried by shoulder I2 of the hollow stationary axle H and secured against a radially outwardly extending flange 81 formed on axle 'II.

The speed responsive means also includes a well known type of governor arrangement comprising a pair of oppositely disposed, radially movable governor weights 90, each pivotally connected to adjacent governor members BI, and

position of the speed responsive means at a prer selected speed.

The governor member 92 includes a tubular extension 94 provided with a shoulder for posi tioning ball bearing means 95 thereon. A re tainer ring 96 secures said bearing means 95 against the shoulder. The outer race of the bearing means 95 carries the switch actuator member 23 which is virtually nonrotatable when the speed responsive means is rotated. The switch actuator member 23 comprises longitudinally oppositely tapering outer annular surfaces 91 which converge at the midportion of the actuator 23 to form a circumferential portion of maximum diameter so as to provide operable contact as at I (Fig. 8) with a roller element I of switch means 24. Thus, when the speed of rotation of the housing is that which has been selected, actuator 23 will depress roller element IOI for closing electrical contacts (not shown) provided by switch means 24.

Means for adjustably and selectively positioning switch means 24 for actuation at preselected speeds of rotation of housing 20 may include a threaded adjustably rotated shaft I03 provided with threaded engagement with a member I04 carrying switch means 24. The shaft I03 may be suitably journaled as at I05 in a plate I06 carried by the axially extending flange 51 on housing portion 5|. The opposite end of the shaft I03 may carry a pinion gear I01 on the outboard side of the partition I8 for connection to position indicating means for the switch means 24.

The pinion gear I01 meshes with a spur gear I09 carried by a stub shaft I I0 mounted in partition 18. The stub shaft IIO carrying spur gear I09 also carries outboardly thereof gear I I I which meshes with a relatively large diameter gear I I2 carried by an inboard extension I I3 of stub axle 60. The outboard face of gear II2 carries a suitable circular disc II4 having on its outboard circumferential margin a plurality of indicia II5 suitably spaced to indicate peripheral feet per minute. A window H0 is provided in end wall 6| of housing portion 52 for viewing the indicia, as best seen in Fig. 6, said window being provided with an index mark I I I.

The end wall 6| includes a threaded bore IIB axially aligned with shaft I03, said bore II8 carrying in threaded engagement an outer closure screw II9. When screw H9 is removed, a headed screw I20 carried by the end of shaft I03 becomes accessible for manually turning shaft I03 to axially move switch means 24 therealong to a selected position as indicated by the indicia through the window II6. In the example shown, the switch means 24 is positioned for 200 peripheral feet per minute. By turning shaft I03, any periphera1 speed may be selected at which it is desired that the switch means 24 be actuated by the actuator 23.

To prevent rotation of switch means 24 during axial adjustment thereof, the member I04 is provided at its lower end with an axially extending groove which slidably accommodates a guide shaft 'I2I, said guide shaft being secured at one end in plate I06 as at I22 and at the other end as at I23 in a shoulder formed on the interior surface of the housing portion 52.

In Fig. 5 the gear means for driving the intermittently actuated switch means 25 is illustrated. The switch means 25 includes a switch element I25 adapted to be intermittently contacted by a cam element I26 carried by a spur gear I21. The spur gear I2! is rotatably driven by a gear I28 mounted on a shaft I29 which extends between the partition I6 and the partition 67. Ad- J'acent partition 61, shaft I29 carires a gear I30 which meshes with a pinion gear I3I carried by a shaft I32 journably mounted in partition 61. The outboard end of shaft I32 carires a gear I33 meshed with the stationary gear 86. Thus, as the housing 20 rotates, cam element I26 is likewise rotated and intermittently contacts the switch element I25 for closing switch contacts (not shown) in switch means 25.

The recording and marking means employed by this invention may be suitably carried or mounted in the cab of the truck, the recording means including a spring-actauted clock shown in Fig. 12 which carries a removable circular chart I4i shown in Fig. 11, the chart being rotated by the clock in a counterclockwise direction as illustrated. The chart I43 includes on its circumferential margin a plurality of radially extending spaced line segments i4! for indicating minutes. The central circular portion of the chart may provide space for pertinent information such as the time of loading, time of pouring the; concrete, total time. of hydration and actual. time the mixer was operated at. the specified peripheral speed. The opposite side. of the chart" (not shown). may include other pertinent data to befilled in by the mixingplant-inspector and job inspector, such data including the number of. sacks of cement, the percentage of water in the sand, the total gallons of water, the percentage of aggregate, the water in the aggregate, the water which had; been added to the,-mix,.the mix designation, the cement brand, cement-testedetc. The chart thus provides a permanent recrd of all pertinent. data pertaining to a batch of concrete carried by the mixing truck. In Fig, 10 is illustrated an exemplary circuit means for actuating'the marking means 25 for recording on a chart I40 the time intervals or periods during which the mixer drum wasrotated at. a selected Peripheral speed, at speeds too fast or too slow, and when the mixer was stopped;

Themarking meansZfiincludes. afirst solenoid I42 having an axially movable solenoid element I43, the outer end of which may be pivotally connected intermediate the endsof marking arm I44 as at I45. The arm I44 may be pivoted about anaxis at I46 and may-carry at one enda suitablepencil, pen or other markingmeans generally indicated at I41. The arm 44 isspring-biased adjacent the other end by a spring I48 connected to said arm I44 and to a suitable member I49 which may be associated with the spring clock means.

A second solenoid I150 is provided with an. axially movable solenoid element I'I' which is pivotally connected as at I52 intermediate the'ends of restraining: arm I53 arranged. transversely of the marking arm I44. One end of arm I53 may be pivotally connected at I54 tomember I49, and at its other-end arm I53 may be provided with a connection to a spring I55 suitably connected to the solenoid I42, the spring I55? biasing arm I53: toward the adjacent end of arm I44. Arm I53 is provided with a shoulder I56 forming a stop to limit oscillation of arm I44 when rotation of the mixing drum is'too slow or too fast, and when solenoid I50 is inoperative.

Solenoid I42 is connected to the intermittently actuated switch means 25 by circuit means indicatedby leads identified as I51, [51a and I51b, said circuit means including a battery source I58. The selectively actuated switch means 24'isconnected with switch-means 25 and the second solenoid I50 by circuit means identifiedby leads I59, I59a, I59b and portions ofleads I51 and; I511). A. light signaling means I590 may be provided in the lead l59b.

In-operation, as the mixing drum rotates, the housing 20 likewiserotates because of its peripheralcontact at 56 with the mixing drum. Rotation of the housing 20 causes the speed responsive means 22 to be driven through stationary gear 86 and the associated gear train in response to the speed of the mixer. Rotation of housing 20 also causes intermittent actuation of switch means 25 by cam element I26. Thus, switch means 25 is closed at intermittent intervals depending upon the speed of rotation of'the hous- When the mixing drum is rotating at selected peripheral speed, the switch actuator 23 closes switch means 24 so that solenoid element I5I of the second solenoid I50 is retracted to hold stop I56. from engagement with the end of arm I44. As the intermittently actuated switch means 25 is intermittently closed, a circuit is completed to. the first. solenoid I42 whereby the solenoid-elemerit I43'is reciprocally axially movable to. cause arm I44. to oscillateabout pivotal axis I46. and to produce on chart I40 arelatively wide. visible zigzag mark indicated at A. Thewide markings at A are readily recognized. and the total number of minutes during which the mixer has rotated at a selected peripheral speed may be readily computed. If the total aggregate sum of marks A on the chart equal a period of fromtwelveto sixteen minutes, the'job inspector will know that concrete in the mixingdrum will have acceptable characteristics (assuming that the proper mix has been placed in. the mixing drum).

When the speedof rotation of-themixing drum is too fast or too slow, the switch meansa24-is-in open position and the. solenoid element I53 of the second solenoid I50- is disposedina nonretracted position wherebystop I56 is adapted. to engage the endof arm I44. Under thiscondiztion, marking arm I44 is provided a limited oscillation or swing about pivotal axis; I 4B-each time that switch means 25 is closed by the intermittently actuating cam I26; Thus, a mark B: of approximately one-half the width" of the marlc A is made on chart I40 and of whioheachcomplete zigzag or oscillatory cycle represents the number of peripheral feet travelled by the; device in one revolution. The-number of cycles in a given period may be counted and the exact speed of too fast or too slow rotation computed.

In the event that rotation of the mixing drum is completely stopped, the switch means: will be in open position and the intermittently ac.- tuated switch means 24 will remain in open 110"- sition. Under this condition, marking, armi I44 is biased by spring I4 8 downwardly into a posittion against a-stop I90'so1that themarkingpemoil at I41 willldraw a; straight. lineindicated at C on chart I40, the. chart beingrotated' at-a constant rate of speed in. a counterclockwise direc:- tion by the spring actuatedclock- 28.

JJ-hus, the chart I 40 willindicate a: record'of conditions wherein the mixing drum isat rest, is rotated at speeds too fast or too slow, and is rotated at a selected speed; It is understood-var.- ious other means may be employed for limiting oscillation of the arm I44 under. various conditions of the. rotation of themixing drum.

The light'signaling means included in the-circuit provides a visible indicating means where by the driver may know when the cement mix.- ing drum is rotatingatoptimum selected speed. By this'signaling device the drivers attention is directed to the maintenance of. proper mixing conditions and he may thereby regulate the speed of rotation so as to: rotate the mixing. drum; at selected speed for a selected period to arrivewith properly mixed concrete on the job.

Installation of electrical connections'between the switch means 24 and 25 carried within the rotatable housing 20 and battery and solenoid associated with the marking means isfacilitated by the stationary hollow axle 11 which affords a conduit means for electrodes or other electric wire means. In the example shown, the hollow axle encloses an outer insulating sleeve I and a spaced inner insulating sleeve ISI. Between said sleeves is provided a suitable tubular elec-- trode I82 and within the inner sleeve I8I maybe provided an electrode rod I83; The electrodes may be suitably connected to electrical. wire means for making the circuit arrangementlshown in Fig. 10.

In Fig. 14 is. illustrated .a differentmodification of a circuit means and solenoid arrangement for producing a record as described above on a rotating time driven chart I48.

In this modification, the actuator 23" is adapted to contact a plurality of independently selectively adjustable switch means I3, I92 and I93, the switch means IE-ii being actuated when the mixing drum is rotated too fast, the switch means I92 being actuated when the mixing drum is rotated at selected speed, and switch means Ids being actuated when the drum is rotating too slow. The switch means I9I, I92 and I93 may be connected to a battery I94 and to a three-stage cumulative solenoid I95 having an axially movable spring-biased solenoid element E95. The switch means I9I is connected to the first stage of the solenoid as at IN, the switch means Hit may be connected to the second stage of the sole noid as at I98 and the switch means I93 may be connected to the third stage of the solenoid as at I99. In operation, when switch means I9I is closed, the solenoid element W6 is positioned as shown in Fig. 14 to produce a straight line indicated by E on the chart and records too fast a speed of rotation for the mixing drum. When the switch means I92 is actuated by the actuator 23 the solenoid element I95 is moved radially inwardly of the chart to provide a mark indicated by line F which is spaced radially inwardly or mark E. When the drum is rotating too slow and switch means I93 is closed, the solenoid element I95 moves to its iurthermost radially inwardly position and provides a mark indicated by line G. Thus, the total time of rotation of the drum at selected speed may be computed by adding the total number of minutes under the marks F, the total aggregate sum indicating the total time period during which the drum was rotating at selected speed.

In Figs. 12 and 13 is illustrated a circuit arrangement and a modification of the recording chart which will provide a foolproof and unchangeable accurate record of the time periods during which the cement mixer has rotated at selected desired speeds. Like parts will be given like reference numerals with a prime sign.

In Fig. 12 the selectively adjustable switch means 24' is shown prior to closing by the switch actuator 23'. The intermittently actuated switch means 25 is illustrated as closed by the cam element I26. The chart I40 may contain on its opposite faces the pertinent data and information described with respect to the chart I40. Indicia MI are printed on the outer circumferential margin of one face of the chart m.

The switch means 24 may be electrically connected to the switch means 25 by a lead IEO. The switch means 25' is connected to a suitable battery II' by a lead IGI. The opposite side of the battery is connected to .a lead I62 which terminates in three spaced contact points I63, IGd'and I65, said contact points being disposed beneath and adjacent to the circumferential margin of chart I40. Lead its is electrically connected as at I66 to a lead It! which is connected to a spark coil I68. The spark coil IBt terminates in an element I69 directly opposed to contact point I64 and onthe opposite side of the chart I40. The switch means 24 is connected by lead I to spark coils III and I12, said spark coils HI and I12 having an element I13 and I'M respectively directly opposed to the respective points I65 and I63 and on the side of the chart opposite to said points.

In operation it will be readily apparent that intermittent closure of switch means it by cam element 126 will intermittently complete a circuit between said switch means and the spark coil I58 and point N54. The spark created by said circuit will burn or char, each time, a single mark such as W5 on indicia it I Since the rotation of cam element I26 is geared to the speed of rotation of the housing the time interval be tween successive closures of switch means 25' is representative of the speed of rotation of the housing and therefor of the mixing drum. Thus the single marks F55 may be spaced at different intervals on the chart; as for example, the widely spaced marks indicated by H show rotation at a slow speed, while closely spaced marks indicated at I, show rotation at a fast speed. If in the example shown intermittent closure of the switch means 25' is geared to one closure for each peripheral feet per minute, the number of marks within a selected time period multiplied by 100 and divided by the minutes of the time period will give the peripheral speed or the mixing drum. When the cement mixing drum is rotating at selected speed so that the switch means 24' is closed, intermittent closure of switch means 25' will fire spark coils I68, III and H2 to thereby burn three radially aligned marks, such as H5, H1 and I18 on the chart. Thus, when the cement mixing drum is rotating at selected speed, the chart will be marked in a foolproof manner to indicate the time periods during which such rotation occurred.

While the modification of Fig. 12 does not show a signal light as illustrated in Fig. 10, it is understood that such a signal light may be included in the circuit arrangement.

In Fig. 15 is illustrated an exemplary circuit arrangement for utilizing the recording device described above on a stationary job site concrete mixing drum. In such a job site concrete mixer, a gate is usually provided for charging or loading the mixing drum and a discharge chute is provided for removal of the mixed concrete from the mixer. It is the purpose of this modification to describe a means and method for accurate recording all pertinent operations of a job site concrete mixer. In such a mixer, it is understood that the mixing drum is normally continuously rotating at a constant selected speed.

In Fig. 15 the circuit means is similar to that shown in Fig. 10 and has been modified to include a switch actuated by the gate and a switch actuated by the discharge chute. Interrupters are provided for oscillating the marking arm under such conditions to provide a distinctive, easily recognizable mark on the chart.

The circuit means includes a selectively adjustable switch means 200 adapted to be closed at selected speed by a speed responsive actuator 205, an intermittently actuated switch means 202 adapted to be closed intermittently by a rotatable cam element 203, a battery source 206, a light signal 205, a first solenoid 206 having an axially movable solenoid element 207 and a second solenoid 208 having an axially movable solenoid element 209 all arranged as in the first described embodiment. The solenoid element 207 is pivotally connected at 2m to a pivoted marking arm 2| I which carries at one end a, marking means generally indicated at 2I2. A chart 2I3 is rotatably driven by suitable time means in counterclockwise direction and is provided with indicia 214 spaced tomeasure minute intervals. The solenoid element 299 'is pivotally connected at 215 to a restraining arm 2 It which is provided with a shoulder M2 for limiting oscillation of the marking arm 2!! in one position as described in the first embodiment. lhe marking arm 2 is spring-biased by a spring 2! and the restraining arm 216 is biased by a spring 2|9.

A gate switch 220 is mounted adjacent a movable gate to the mixing drum for actuation by said gate. When 'the'gate is closed fora mixing operation of the drum, the gate switch 220 is in the position illustrated in Fig. and provides a completedcircuit between the switch means 202, battery 204 and solenoid 206 as identified by leads 221, 2-22, '223and 224. In gateclosed position, gate switch 220 provides a circuit including the intermittently actuated switch means 202 for intermittentoscillation of the marking arm 2H by "the first solenoid 202.

The discharge chute, when in closed position or in a-position'when the mixing drum is operating to mix a batch of concrete, is adapted to close a discharge chute switch means 2-25 soas to permit normal actuation of the marking arm 2-H for recording aselected speed, too fast or too slow speeds, and-astop condition asdescribed in the firstembodiment. In-closed position, switch means 225 provides a circuit through leads 226, 221,222,223, 224 and 221 for permitting operation of solenoid 206 by the intermittently actuated switch means 202.

Thus, the circuit means shown in Fig. 15 will permitoperation of the solenoids 206 and2c8 in the manner described in the first embodiment whereby rotation-of the mixer at selected speed will be identified by marks -Aonchart 2+3, rotationof marks at too fast or too slow a speed "will be identified by marks B on chart 2 l3 and when the mixer is not rotating, a straight line mark will be provided on chart 213 as indicated by mark-C.

When the concrete mixing drum is being rotated and the gate is in 'open position, the gate switch means 220 is actuated into the position indicated by phantom linesat228 and opens the circuit for actuation of switch means 202 and closes a-circuit for bringing into operation 'a suitably selected interrupter means 229, the interrupter means 2 29 providing rapid oscillation of marking arm 2H. The rapid oscillation of marking arm 2 H provides a narrow, dense markon-chart 213 as indicated at K. The number-of minutes covered by mark K will indicate the amount of time that the mixer was being charged.

When the concrete has been mixed and the discharge chute lowered 'to discharge the concrete from the mixer, the switch means 225 will be moved to the position indicated by phantom lines at 230. In this position, the discharge switch means opens the circuit which includes the intermittently actuated switch 202 and closes a circuit containing suitable interrupter means 23!. The interrupter 23l causes rapid oscillation of the solenoid element 201 to rapidly oscillate'marking arm'2'l I to provide a dense narrow mark indicated by L on chart 2 l3. Since the interrupters are selected with difierent interrupter frequency characteristics themarks K and L will appear as different marks both in density and in width so as to be readily recognized.

it is assumed in "the above explanation of the operation of "the circuit means that the mixing drum is not rotating at selected speed. A suit- 12 able gang switch means (not shown) may be provided adjacent to the gate switch means 220 and the discharge chute means 225 for-openingand closing the circuit which includes the selectively actuated switch means 200.

It should be noted that in the 'marks'B'end B shown in the first embodiment, the number of oscillations within the interval between minute indicium indicates the speed at which themixin'g drum was rotated. For example, 'if the peripheral speed of the mixing drum was "feet per second, and the cam element 203 w-as geared to actuate the switch means 202 for each revolution, when the selected speed' was "200 feet per J minute, there would be two zigzag cycles within the interval between adjacent minute indicia -'on the chart. If the speed of rotationof the mixer was considerably less, the zigzag cycle would "be greatly extended so that the number of oscillations divided by the number of minutes-covered by the zigzag line would give the speed of the mixing drum over a specified time period. When the mixin drum was rotating too faster over 200 peripheral feet per minute, the zigzag line would be relatively dense as indicated at M, and counting the number of zigzagcycles within the selected time period would indicate "how f ast the mixing drum was rotating.

It should also be noted that the speed responsive actuator may be provided with a flattened circumferential portion adapted tomaint-aincontact with the switch means 24 over a practical range of selected peripheral speeds, as for example, to 205 peripheral feet per minute. Mixing of concrete within this exemplary range for practical purposes will produce acceptable concrete.

It is understood that suitable means may be provided for breaking the circuit to the marking means in the event the drum should'come 'to rest with one or both of the switch means in closed position, such a closed "circuit condition having detrimental effecton the solenoids of the marking-means.

It will thus be readily apparent to those skilled in the art that a means and method have been provided by the above-described device which will accurately record data concerning mixing conditions taking place in'a cement mixing drum carriedfby a truck While in transit between a proportioning plant and a job. Such a device provides a record of mixingconditions which has not heretofore been attained. The advantages. of recording the exact mixing conditions while the truck is in transit not only insures that only acceptable concrete is provided for "the .JTo'b,,but also results in saving time since the driver may. make certain that the concrete is properly mixed when he reaches his destination.

It is understood that other modifications and.-

changes may be made in the device described above and all such modifications coming within the scope of the appended claims are embraced thereby.

We claim:

'1. In a. device for measuring and recording. mixing conditions for a rotatable concrete mixing drum, the combination of: a pivotally mounted rotatable hollow housing; spring means. for biasing said housing into rolling engagement. with a periphery of said drum; speed responsive means operable within said housing and including an axially movable switch actuator member;

ing means for said chart; and circuit means including switch means within said housing intermittently actuated by rotation of said housing into closed position, adjustably positioned switch means carried within said housing in cooperable relationship to said actuator member and adapted to be closed thereby when the housing is rotating at a preselected speed, and solenoid means electrically connected to both switch means for oscillating said marking means when both switch means are in closed position.

2. In a device for measuring and recording mixing conditions for a rotatable concrete mixing drum, the combination of: a pivotally mounted rotatable hollow housing; spring means for biasing said housing into rolling engagement with a periphery of said drum; speed responsive means operable within said housing and including an axially movable switch actuator member; a movable record chart provided with time indicia; time means for moving said chart; marking means for said chart; and circuit means including switch means within said housing intermittently actuated by rotation of said nousing into closed position, adjustably positioned switch means carried within said housing in cooperable relationship to said actuator member and adapted to be closed thereby when the housing is rotating at a preselected speed; said marking means being operably connected to both switch means for distinctively marking said chart when both switch means are closed for indicating time intervals when the mixing drum is rotated at selected speed.

8. A device as claimed in claim 2, wherein the adjustably positionable switch means is axially movable parallel to the actuator member.

4. A device as claimed in claim 2, wherein indicia means are cooperably associated with the adjustably positionable switch means for indicating the position of said positionable switch means with respect to the actuator member.

5. A device as claimed in claim 2, wherein the marking means includes a plurality of radially aligned spark coils adjacent to one face of the chart and respectively opposed contact points adjacent to the opposite face of the chart for burning a mark on said chart when both said switch means are closed.

6. In a device for recording mixing conditions of a concrete mixing drum including a housing adapted to be rotated by said drum, means operable within said housing in response to the speed of rotation of said drum, and a rotatable time driven chart, the provision of: a switch actuator member movable by said speed responsive means; a switch means adjustably movable in relation to the switch actuator member and cooperable therewith to be closed when the drum is rotated at a preselected speed; a second switch means normally in open position and intermittently actuated to closed position; marking means for the chart movable transversely thereof when both switch means are in closed position; and means electrically connecting both said switch means and marking means.

7. A device as defined in claim 6, wherein the marking means includes a marking arm, a spring biasing said marking arm into one position and a solenoid means connected to said marking arm for oscillating said arm.

8. In a device for recording mixing conditions of a concrete mixing drum including a housing adapted to be rotated by said drum, means operable within said housing in response to the speed of rotation of said drum, and a rotatable time driven chart, the provision of: a switch actuator. member movable by said speed responsive means; a switch means adjustably movable in relation to the switch actuator member and cooperable therewith to be closed when the drum is rotated at a preselected speed; a second switch means normally in open position and intermittently actuated to closed position; marking means including spark means adjacent to said chart and energized by closure of said switch means; and means electrically connecting both said switch means and marking means.

9. In a device for recording mixing conditions of a concrete mixing drum including a housing adapted to be rotated by said drum, means operable within said housing in response to the speed of rotation of said drum, and a rotatable time driven chart, the provision of a switch actuator member movable by said speed responsive means; a switch means adjustably movable in relation to the switch actuator member and cooperable therewith to be closed when the drum is rotated at a preselected speed; a second switch means normally in open position and intermittently actuated to closed position; marking means including a plurality of radially aligned spark means disposed adjacent to said chart, one of said spark means being energized when said second switch means is actuated to closed position and the other spark means being energized when the adjustably movable switch means is actuated to closed position, whereby a plurality of radially aligned burned marks are made on said chart for indicating time periods when the drum is rotating at selected speed; and means electrically connecting both said switch means and marking means.

10. In combination with a mixing drum, a device for recording mixing operations of said drum including a housing adapted to be rotated by said drum, means operable within said housing in response to the speed of rotation of said drum, a rotatable time-driven chart, said drum including a charging gate and a discharge chute, the provision of a switch actuator member movable by said speed responsive means; a first switch means adjustably movable in relation to the switch actuator member and cooperable therewith to be closed when the drum is rotated at a preselected speed; a second switch means normally in open position and. intermittently actuated to closed position by rotation of said housing; marking means disposed adjacent to said chart and normally adapted to be oscillated by intermittent closure of said second switch means to mark said chart in accordance with the speed of rotation of said drum, said marking means being operable when said second switch means and said first switch means are closed to indicate on said chart rotation of the drum at selected speed; interrupter means and gate operated switch means; a second interrupter means and a discharge chute operated switch means; circuit means to electrically connect said switch means and interrupter means; said gate operated switch means in one position closing a circuit between said intermittently actuated switch means and the marking means, and in another position closing a circuit for said interrupter means and said marking means whereby said marking means is rapidly oscillated when the charging gate is opened; said discharge chute operated switch means in one position closing a circuit between said intermittently actuated switch means and said marking means and in another positionclosing a circuit between said marking means and the second interrupter means wherebysaid marking means is oscillated to indicate on said chart the time period during which thedischarge chute is in discharge position.

'llvlnra device for measuring and recording mixing conditions fora rotatable mixing drum, the combination of: a hollowhousing'; speedresponsive means operable Within said housingiand including an axially movable switch actuator member; a rotatablerecord chart provided'with time indicia; time means for rotating said chart; marking means for said chart; and circult'me'ans including switch means Within said housing :intermittently actuated into closed position in response to the speed of rotation of the mixing drum, adjustablypositioned switch means carried within saidhousingin cooper-able relationship'to said actuator member and adapted "to be closed thereby when the mixing drumisrotating at preselected specd; said marking means being operably connected to both switch means for'niarking said chartin response to closure or each switch means for indicating time intervals when the mixing drum is rotated at selected speed and at speeds slowerandiaster than selected speeds.

12. A device as recited in claim 'llwherein the marking mean's includes a marking arm, a spring biasing said marking arm into one position; a solenoid -means connected to said marking arm for oscillating 'saidarm, and stop means cooperable with said marking arm for limiting oscillationthereof.

13. A device as recited in claim 12 wherein a solenoid means is connected to said stop means, said latter solenoid means being actuated by said switch actuator member'to release said marking arm from engagement with said stop means for producing a distinctive mark on said chart when the mixing drum is rotated at selected speed.

14. 'In a device for recording mixing conditions for a rotatable mixing drum, the combination of: recording means for intelligibly indicatingselected conditions of rotation'of said mixing drum; means responsive to rotation of said drum and positioned adjacent thereto, said responsive means including a first normally open "switch meansand actuatingmeans'therefor to intermittently close said switch means in response to each "revolution of said drum; adjustably :positioned second normally open switch means and actuating means therefor responsive'to' the speed of rotation of said drum and to close the second switch means at a preselected speed of rotation of the drum; and circuit means operably connecting said first and second switch means and said recording means for recording in response to closed positions or'each of said switchmeans.

RAYMOND G.'OSBORNE.

ROBERT O. BOYKIN.

References Cited in the file of this patent UNITED STATES PATENTS 507,548 Great Britain June 16, 1939 

